During air cooling of steel balls, the convection heat transfer coefficient is determined experimentally as a func- tion of air velocity to be h 17.9v054 for 0.5 < v< 2 m/s, where h and v are in w/m2.k and m/s, respectively. consider a 24-mm-diameter steel ball initially at 300°c with a thermal conductivity of 15 w/m-k. the steel balls are cooled in air at 10°c and a velocity of 1.5 m/s. determine the initial values of the heat flux and the temperature gradient in the steel ball at the surface.

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.

Water at 55c flows across a flat plate whose surface temperature is held constant at 95c. if the temperature gradient at the plate's surface for a given value of x is 18 c/mm, find a) local heat transfer coefficient. b) heat flux

True or false (explain) (110)[111] is a slip system in bcc metals . the {111} family in fcc contains 8 planes. resolved shear stress (rss) in single crystals is just related to the applied stress. critical resolved shear stress (crss) in single crystal metals is direct proportional to the number of defects in the structure